Stamped-metal access plate for gearboxes



Nov. 30, 1954 H. B. CHATFIELD 2,695,726

STAMPED-METAL ACCESS PLATE FOR yGEARBOXES Filed Jan. 8. 1951 2sheets-shet i INVEN TOR. HENRY B-C//ATF/ELD BY KM.

A TTOIP/VEYS United States Patent C) STAMPED-METAL ACCESS PLATE FOR-GEARBOXES Hem-.y B. Chatlield, Kinsman Ohio,

Application lJanuary! 8 1951, Serial` No. 204,990

101Cl'aims., (Cl. 22m-415)v 'Dhisinvention relates to a process and theproduct; of;

at process for. manufacturing.stamped-metal` access plates for gearboxes, transmission. casings, pumps, reactors,

pressure vessels., and similar movable and immovable units. making; useofi a. housing of somel suitable, kind` in which at tight seal is.desired between.. the housmg; and

the access plate. Heretofore, access. platesA for these. purposes. haveordinarily` been made in.4 theA form of` castings, of malleablefastening elements, the access. plate is located andheld` intplaceton.the housing. Such, accesszplartes .are .relatively expensive tovmanufacture. Up` to they presentl time, savings; ofimpressiveproportions in 'materials `and costs have;

been sacriii'cedl that would have been enjoyed if satisfactory:accessfplates` could: have been made of metal starnpings;` however, ithas not heretofore been known how to make. stamped-metal access; platesthat would' give.,` the;` desired. sealing action between. the'v seatingsurfacesf, on the access plate and.v theycoopera-ting:surfaces onthehousing.

Previous attempts. to` manufacture stamped-metal access plates, of whichthere have been. many, havebeen aimed at; obtaining, aA seal by=maintaining the. sealing surface atwithin: one or two thonsandthslof.an. inch: this; 'hask resulted in` excessive scrap, excessive diemaintenance, or the,` additioni of a. surface4 grinding operation.

It. is. an. object: of the-present: invention to provide astampedemetal, access plate, and' in. some aspects ofthe inventionAanaccessplate that isfbuilt up of a. plurality of metal; stampingsthatmay. beA used inA lieu` of the castmetaltaccess plates. ofthekindsheretofore generally. employed, It is a further. objectl of theinvention to.provide a, stamped-metal.l access.` plate that will giveIthe` desired sealing; action, this even when substantial pressuresmust bej resisted. It is al further object of, the invention to provide; astamped-metal access plate` that'. permits.` a` substantially constantsealing pressure to be maintained at alltpoints along` the sealingsurface. It isfstill a further objectof theA invention `toreduce`.the-cost of accesslplates to ,a minor. fraction of thegcosnof;cast-metal; access` plates of` thikindsgheretofore used. Gtherobjectsandaadlvan- .tagesl ofY theV invention willb'e apparent. from:`theidescription which.follows as well as fromv the accompanyingdrawings.

In thefdrawings,Figure;1` isa topplan of' the preferred tyBe-of;accessgplateshowing the; same after the channellikestructureencompassingthefbody portionof the access-plate'hasxbeenstruck; fromthe; blank. Figure@ is a sectionondine Z-ZrofpFigure 1. lookingin.thedirection ofthe-arrows. Figure 3 is a topplanof .the4 accessplateat` aJater, stage in theprocess ofr manufacture. Figure4 isa, sectionsimilar to that of Figure 2f on line 4-4.of Figure, FigureyS is,ratopplanaof the access plate at a,st.ll.1aterstage1inthe process'ofmanufacture. Figure 6 By;I contrast-withFiguresl to 9, all. of; whicharexonia. reduced, scale, Figures l0 to 141- aref of ullsvsizel.AFigure` 1.01is a View` partly in` verticab central section andtipartlyv4inl side elevation of the preferred` type: of access: pla-tez applied tothe top of a.A gear box. Figure.: lil; is; a view' partly in verticalcentral section. and partly.1 in. side. elevation of a modified. form ofan access;plate,.likewise applied toa gear. box; Figure 12 is adetailzof themodiiied` form of :access plate seen.` in` endI elevationas if from. the. left: hand endof Figure. ll. Figure. lf3. is` a similarview` of. the channel forming. partof the modified form:- of accessplate. Figure 14 is a transverse vertical section. with parts inelevation through an access plate ofy theoil` pan type that isfor-medina manner. otherwise analogous to that ofthe preferred type; ofaccesspla'te of. Figures l to. 10, inclusive.

The access` plate shown in'iinished formtin Figures 6, 8 and 10` isshown alsoz in applicants copending application Serial No. 204,989,led.l'anuary'8,.195l,.for AccessPlate.

In the form in which it is shown; in Figures l and. 2, the preferredvtype of access plate, generally designated.' l in Figures l to 9,inclusive, isin an early stage inthe process of its manufacture. At thisstage,A a flat sheetmetal. blank of appropriate shape` has been givenpre.- liminary form by subjecting it to the action of two cooperatingdies, male and female. It hasa flat bodyportion 2` that as. shown. ispolygonal but maybe of any other desired shape; e. g., rectangular,square,.circular, etc. Body portion 2x is surrounded by an.encompassingV peripheralv channel 3" that has been struck up from theblank by the action` ofv the dies. As appears from Fig-t ure 2,peripheralchannel'isgenerally U-shaped in crosssection, beingcharacterized by an inner wall 4 risingv abruptly from bodylportion 2,an intermediate portion' 5 extending outwardly ina manner permitting itto serve asthe bottom portion or base of channel 3, andianouter wall `6.parallelinginner wall 4'; Depending from. outer wally 6: -below theplane ofi body portion 2 are flash-likeears 7 which are removed by. a`suitable operation, such as .pinch-trimming.

After the. incompletely formed` access plate has been trimmed toveliminate ears 7, it isworked` between a second: pair of cooperatingdies.torestrike peripheralchannel 3 to the desired linished size. Inthis same operation,. locating bosses 9` are formed in inner wall 4` ofchannel. 3, such. bosses projecting: toward the interior ofi .theaccessplate in themanner. most clearly shown in Figure 3. Inthe sameoperation, or, if desired; by. a separate operation, those: portions oftheaccess plateatwhic'hinner wall 4' of channel 3 impinges onV body`portion 2 are det`o1med`,.as` by pressure applied from above by a die,to. form. a; smoothly-faired convex or downwardly bowed portion 10 inthe stretches between4 adjacent bosses 9.

Suchrconvex portions lllusually have a radius ofcurva- `ture so great:that: the convexity is almost imperceptible to the eye; nevertheless,each of them as Viewedl inside elevation. presents the generalconfiguration of a shallowr catenary or like curve. Convex portions 1l),which appcarin exaggerated fashion.` in Figure 4 and subsequent figures,willordinarily have a maximum heightl of: more than about 0.001 but lessthan about 0.090 inch, measured from, the proximate plane. of body.portion 2; Theprecise value, which is. a function-of the pressure to beretained,` the distances betweenfastening elements and the nature of thefastening elements themselves, should be lessttlian-that amount whichwould give `risexto permanent flattening as a. result of the impositiono'f forces exceeding the` elasticlimit of the, metal upon applicationofthe fastening elements to the access plate;

The result of forming convex portions `10 is to introduce into what maybe regardedas the edge of inner wall 4 of` peripheral channel. 3 aplurality of widely spaced longitudinally extending undulations, such`undulations being of maximum height, measured from the proximate planeof body portion 2, approximately mid-way between each two adjacent'-bosses` 9. Although, as indicated above,` preferred practice involves`forming convex porticnsflO. in the same .operationin which peripheralchannell` 3,: is' 11e-struckn and bosses 9. are. introduced intoV itslinner wall, the; undulations may, ifl desired, bedeveloped in. anyrother desired; way or` at some` other. stage f in the;

3 process of manufacture of access plate 1. Usually, however, it will bedesirable to form the undulations before undertaking the operationsdescribed hereinafter.

Convex portions 10 having been formed in some suitable way, the nextfollowing operation may conveniently be the opera-tion of formingoutwardly of bosses 9 the at portions 11 (iiats) which appear in Figure5 and subsequent igures. This likewise is done by means of cooperatingdies. Simultaneously therewith, it is convenient to coin the oppositeface of access plate 1. Such coining operation is for the purpose ofproviding smooth surfaces on those portions of access plate 1 underlylnginner wall 4 of channel 3; i. e., those portions of access plate 1 atwhich peripheral channel 3 impinges on body portion 2.

lIn the course of the coining operation, a groove 13 (Figure 6) isproduced on the top face of the access plate and smooth seating surfaces14 (Figure 9) are developed on the bottom face of the access plate. Thecoining operation should not be carried so far as to destroy thecatenary-like curves of convex portions 1t); however, a small part ofthe original convexity is of course eliminated by the coining step. Theamount of material removed is important in the sense that enoughconvexity must'remain so that the convexity, measured from the proximateplane of body portion 2, exceeds the aggregate of the manufacturingtolerances on the opposed portions of the housing, access plate, andgasket.

After introducing flats 1'1 and performing the coining operation givingrise to grooves 13 and seating surfaces 14 on the obverse and reversesides of access plate 1, respectively, means for attaching the accessplate to the housing are incorporated in it. While various ways ofattaching the access plate to the housing may be employed, preferredpractice involves the introduction of openings of suitable size andshape, such, for example, as circular holes 12, one at the geometricalcenter of each of flats 11. This may be done by piercing, punching or inany other suitable way, giving the finished access plate, viewed fromabove, the appearance indicated in Figure 6. Viewed from below, thefinished access plate has the appearance presented by the bottom planconstituting Figure 9 of the drawings. `In a typical case, the accessplate illustrated on a somewhat reduced scale in Figures l to 9 has anoverall length, measured from side to side in Figure 6, of approximatelyinches and an overall width of approxim-ately 41/2 inches. Channel 3 mayhave an overall height of about inch, measuring from the bottom of bodyportion 2 to the top of channel 3. The width lof channel 3 at its edges;that is to say, the width of the opening as measured in the plane ofbody portion 2, may be of the order of about 1A inch. Hole 12 in iiats11 adjacent bosses 9 may in such case be spaced about 21/2 inches fromeach other. Obviously, all of these dimensions and the ratios betweenthem may be varied within very wide limits.

The preferred type of access plate is of sheet steel of relatively heavygauge; e. g., l3-gauge, .and of one of the many compositi-ons lendingthemselves to st-amping and use in access plates of the kind described,although it may, if desired, be formed of suitable non-ferrous metal.

Figure l0 shows access plate 1 applied to a gear box 15 having anopening 16 through which access may be had to the interior of the gearbox. Extending upward from gear box 15 are studs 17, the same beingsuitably located around the periphery of opening 16. Onto studs 17 arethreaded the nuts 18, the latter seating on flats 1'1 adjacent locatingbosses 9. Between the access plate and the gear box is a gasket 19,which may be made of oil-impregnated kraft paper about .010 inch inthickness. ln seating on gear box 15, the convex portions of the accessplate giving the undulatory elect to lthe seating surface come firstinto contact with the gasket 19 appr-oximately mid-way of the stretchesbetween studs 17; thereafter, as nuts 18 are screwed home, the otherportions of the seating surface of the access plate, including those inwhich locating bosses 9 are formed, come progressively into contact withthe gasket, compressing it against gear box 15.

The modified form of access plate shown in Figures ll to 13 is made upof two metal stampings, one of them a substantially at sheet 21,provided, if desired, with one or more reinforcing ribs 22, which sheetserves as the body portion of the access plate. Impinging upon bodyportion 21 is the separately formed peripheral channel 23, the samebeing generally U-shaped in cross-section and consisting of an innerwall 24, an outer wall 25, andv a substantially iiat connecting portion26. Channel 23 is formed with spaced indentations 27 in its inner andouter walls, such indentations locating the means for positioning andattaching the fastening elements (studs 17 and nuts 18) that hold theaccess plate to gear box 15. Such means include registering openings ingasket 19, body portion 21 and connecting portion 26 between inner wall24 and outer wall 25.

The edge of inner wall 24, and, if desired, also the edge of outer wall25, is bowed between adjacent openings in a manner analogous to thebowing provided by convex portions 10 in the access plate of Figures 1to 10, inclusive. Although shown in greatly exaggerated fashion, thebowing of the edge of inner wall 24 appears at 24a in Figure 13, whichrepresents a channel in which the edge of the inner wall is bowed andthe edge of the outer wall is not bowed. This bowing of the edge of theinner wall of the encompassing structure is communicated to body portion21. When the built-up access plate of Figure 1l is applied to gear box'15, sealing action is obtained -both where the bowed portions overliethe edges of access opening 16 and where nuts 18 on studs 17 urge theparts together.

For 4the purpose of holding channel 23 in place on body portion 21, thelatter is provided at each end with a projection 28 which carries aninwardly extending tang. 29. Tangs 29 are preferably integral withprojections 28 and the latter are preferably integral with 'body portion21. When the parts are assembled to form the access plate, each tang 29is forced into a recess 30 in outer wall 2S of peripheral channel 23,thus providing a mechanical interlocking of the parts as indicated, forexample, in Figure l2. While this construction maybe used not only atthe ends but also along the sides of the access plate, two are suicientin an ordinary case to hold peripheral channel 23 firmly in place onbody portion 21.

If desired, in each of these embodiments of the invention, the outerwall of the peripheral channelmay be interrupted or even largelyeliminated, leaving an encompassing structure -that may nevertheless bedescribed as channel-like in the sense that when the access plate isapplied to a gear box or the like, the resulting open-sided hollow hasthe characteristics of a laterally extending or outwardly facingchannel.

In each of the forms of the invention heretofore described, theencompassing structure is of a height greater than the maximum height ofthe intervening body portion. It is of course possible to have lthe bodyportion raised above or depressed below the encompassing structure. Thisis illustrated in Figure 14, which shows an integrally formed accessplate of the oil-pan type, such access plate 'being applied to a housing32 having an opening 33 from which it is separated from a gasket 34 andto which it is aixed by bolts 35. The body portion 36 of the accessplate is offset from the seating surfaces at the edge of Ithe inner wallof the channel. Between side wall 37 and the channel is a hollow 38 intowhich the tool used in the coining operation enters when the seatingsurfaces are formed. l

Thus the invention provides a stamped-metal laccess plate in whichsealing contact with the gasket or, lacking a gasket, with the housingitself is established tirst ap proximately midway of the stretchesbetween adjoining fastening elements. As the fastening elements are madetight, those portions of the access plate which do not make such-contact initially; e. g., the portions of the access plate adjacent thefastening elements, are urged progressively into position, this lbeingpossible because of the inherent resilience of the metal itself. Asubstantially constant sealing pressure thus may be achieved andmaintained along lthe entire sealing surface. Ilf desired, however, theoverall amplitude of the undulations as measured from the body portionof the access plate can be increased to a point where the pressure,disregarding manufacture tolerances, is greater mid-way `betweenfastening elements than elsewhere, this being the precise opposite ofthe condition that obtains in ordinary access plates of the kindsheretofore used.

It is apparent that numerous modiications and departures may beintroduced into the stamped-metal access plates described in theforegoing specification. The preferred construction is an integralconstruction of the kind illustrated in Figures 1 to 10 and14. 'Howevenas illustrated in Figures 11 to 13, a stamped access plate may, ifdesired, be formed of a plurality of separate` sheet metal stampings.Elaborated forms of the invention made up of several such sheet metalstampings may readily be devised. As a general rule, they also will becharacterized by a convexity or bowing providing a series of spacedundulations where the encompassing structure impinges upon or joins thebody portion of the access plate.

It is intended that the patent shall cover, by surnmarization in theappended claims, whatever features of patentable novelty reside in theinvention.

What is claimed is:

1. A stamped-metal access plate for a gear box or the like comprising asheet metal stamping having a body portion; a seating portion on oneside of the stamping near the periphery of the body portion, saidseating portion being characterized by the presence therein of asuccession of longitudinally extending undulations each of which issmoothly faired into the preceding and following undulations; and, onthe opposite side of the stamping, a channel characterized by aninverted U- shaped cross-section having its bottom portion raised abovethe seating portion and in it integrally formed means adapted to receivethe elements used in fastening the access plate in position, saidintegrally formed means and said seating portion being spaced from eachother with the former offset from the latter in that dixection whichleads away from the interior of the gear ox. t

2. An access plate as in claim 1 in which the channel is formedseparately from the rest of the access plate.

3. A stamped-metal access plate for a gear box or the like comprising asheet metal stamping having a body portion; a seating portion on oneside of the stamping near the periphery of the body portion, saidseating portion being characterized by the presence therein of asuccession of longitudinally extending undulations each of which issmoothly faired into the preceding and following undulations; and, onthe opposite side of the stamping, a channel characterized by aninverted U- shaped cross-section, one wall of which impinges upon thebody portion of the access plate, the bottom portion of said channelbeing oifset from the general plane of said seating portion in thatdirection which leads away L,

from the interior of the gear box and having in it integrally formedmeans accommodating the elements used in fastening the access plate tothe gear box.

4. A stamped-metal access plate for a gear box or the like comprising asheet metal stamping having a body portion; a seating portion on oneside of the stamping near the periphery of the body portion, saidseating portion being characterized by the presence therein of asuccession of longitudinally extending undulations each of which issmoothly faired into the preceding and foli lowing undulations; and, onthe opposite side of the stamping, a channel characterized by aninverted U- shaped cross-section, which channel impinges upon the bodyportion of the access plate along the edge portion of its outer wall,the bottom portion of said channel being olfset from the general planeof said seating portion in that direction which leads away from theinterior of the gear box and having in it integrally formed meansaccommodating the elements used in fastening the access plate to thegear box.

5. A stamped-metal access plate for a gear box or the like comprising asheet metal stamping having a body portion; a seating portion on oneside of the stamping near the periphery of the body portion, saidseating portion being characterized by the presence therein of asuccession of longitudinally extending undulations each of which issmoothly faired into the preceding and following undulations; and, onthe opposite side of the stamping, a channel characterized by aninverted U-shaped crosssection which channel impinges upon the bodyportion of the access plate both along the edge portion of its innerwall and along the edge portion of its outer wall, the bottom portion ofsaid channel being offset from the general plane of said seating portionin that direction which leads away from the interior of the gear box andhaving in it integrally formed means accommodating the elements used infastening the access plate to the gear box.

6. An access plate as in claim 5 in which the body portion and thechannel are held together in the desired relation to each other by meansof extensions on one which project into recesses in the other.

7. An access plate as in claim 6 in which the channel is provided withrecesses in which are received reversely bent tangs formed integrallywith the body portion.

8. A stamped-metal access plate for a gear box or the like comprising asheet metal stamping having a body portion; an undulatory seatingportion on one side of the stamping near the periphery of the bodyportion; and, on the opposite side of the stamping, a channel having aninverted U-shaped cross-section the bottom of which channel is offsetfrom the general plane of said seating portion in that direction whichleads away from the interior of the gear box, said channel impingingupon the body portion of the access plate along the edge portion of theinner wall of the channel and having outwardly of said inner wall aseries of openings for receiving the IeJlements used in fastening theaccess plate to the gear 9. A stamped-metal access plate for a gear boxor the like comprising a sheet metal stamping having a body portion; anundulatory seating portion on one side of the stamping near theperiphery of the body portion; and, on the opposite side of thestamping, a channel having an inverted U-shaped cross-section thebottom` of which channel is offset from the general plane of saidseating portion in that direction which leads away from the interior ofthe gear box, said channel impinging upon the body portion of the accessplate along the edge portion of the outer wall of the channel and havinginwardly of said outer wall a series of openings for receiving theelements used in fastening the access plate to the gear box.

10. A stamped-metal access plate for a gear box or the like comprising asheet metal stamping having a body portion; an undulatory seatingportion on one side of the stamping near the periphery of the bodyportion; and, on the opposite side of the stamping, a channel having aninverted U-shaped cross-section the bottom of which channel is offsetfrom the general plane of said seating portion in that direction which.leads away from the interior of the gear box, said channel impingingupon the body portion of the access plate both along the edge portion ofthe inner wall and along the edge portion of the outer wall of thechannel and having between said inner wall and said outer wall a seriesof openings for receiving the elements used in fastening the accessplate to the gear box.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,857,443 Draper May 10, 1932 1,890,936 Douglass Dec. 13, 19321,961,121 Knapp May 29, 1934 2,272,178 McDowell et al. Feb. 10, 1942

